When modifing the test items page, it's nice to haveconsistency in the collapse/expansion of test items. Let's say, in your test items page, you have a folder with a set of test child items. While the project is open, that folder is expanded - showing the child items for display. However, when you close the project and reopen it, the test items folder collapses - hiding your child test items.
If you have a team working on the same project, it will be convenient that, when they open the project on the machine, they see the state of test items to which they are working with.